Method of rendering insufficiently-ductile metals ductile.



CARL TRENZEN, 0F COLGGNE-BRAUNSFELD, GERMANY.

I TIIETHOB (3E? BElElDERINQ l IENSUFFICIENTLY-DUCTILE METALS DUC'IILE.

N0 I'Erawing.

Specification of Letters Eateilt.

Patented Get. '5, 19135.

Application filed June 17, 1913. Serial No. 274,270.

To (all whom it may concern Es it known that l, CARL Tusuanrr, a subject of the German Emperor, and resident of Cologne-Brauns.teld, in the Kingdom of Prussia, German Empire, have invented new and useiful improvements in Methods of Rendering lnsulficiently-lluctile Metals Ductile, of which the following is a full, clear, and exact specification.

it has already been long known to treat tungsten or other metals which are non-ductile or but slightly ductile l subjecting them to prolonged mechanical working by which an increase of density is brought about or the molecules are pressed closer together in such a way that a sort of felt-like or fibrous structure is produced which hinders the separation of the particles in a subsequent drawing operation. y this method, for which metal free from oxid must be used, non-ductile or but slightly ductile i'uetals can be made ductile enough to be drawn. Another method that has been attempted is to hammer or otherwise mechanically work the metal while hot. Further, it has been proposed to subject filaments to gas pressure while heated byelcctric currents.

T he proposal of the present invention is to effect the desired consolidation producing a felt-like or fibrous structure by highly compressing amorphous metal, for example tungsten, while at a high temperature, which. facilitates the interfiow of the particles. -l'cwrever, when heated in this way to a cer- 1 temperature varying according to the 11;; conditions and the nature and prope1 ies of themetal under treatment, but constant for constant conditions, the amorphous starting materials becomecrystalline. Hereby it becomes impossible or at least much more difiicultto obtain the desired consolidation. The particular temperature at which this change from the amorphous to the crystalline condition ccurs can not be predicted, but must be determined experimentally. As a practical example, the following may serve: When heated in an atmosphere of ordinary hydrogen of commerce, passing through the press, the material must be heated for approximately ten minutes and to about 950 degrees ccntigrade before applying the pressure. Now I have found that this passage from the amorphous to the crystalline condition can be avoided if the mechanical treatment begins at the very momentwhenthe above mentioned temperature is reached. If for instance at this temperature the metal is siibjected to a high pressure, it does not pass from the amorphous to the crystalline condition, but takes the desired fibrous structure which is a condition of its ductility. For instance, the method may be carried out by highly heating in a press cylinder, say electrically, metal bars which have previously been sintered, and then exposing them to a considerable hydraulic pressure, if the temperature referred to has been reached. Heating can then be continued and the temperature increased without any danger of the metal becoming crystalline. The critical temperature must, of course, be ascertained by a preliminary test. In this way it is possible to make, for instance, metals like tungsten, which are not very readily drawn, more ductile.

The methodhas the further advantage that oxidizable metals such as tungsten are transformed to a condition in which they are less liable to oxidation so that the metal may be further treated by rolling and drawing out at comparatively high temperatures up to a dull red heatwithout fear of any considerable oxidation.

It is a condition for the successful applica tion of this method that the metal before its treatment shall not have been exposed to any temperature at which it would assume a crystalline structure, and that it shall not contain the least trace of oxid, for otherwise the compression could not produce any cohesion.

What I claim is 1. The method of, rendering insuliiciently ductile metals ductile, through increase in density, consisting in heating the metal in amorphous condition to a high temperature and at the moment when, as a result of said heating, it would pass to the crystalline state subjecting it to considerable pressure.

2. The method of rendering tungsten metal ductile, through increase in density, consisting in heating amorphous tungsten to a high temperature and at the moment when, as a result of said heating, it would pass to the crystalline state subjecting it to considerable pressure.

The method of rendering tungsten metal ductile, through increase in density, as my invention, 1 have signml my name in consisting in hez lting amorphous tungsten in presonvo of two subscribing Witnesses. an atxnosphero of hydrogen for approxnnatelz CAR L T I ENZ E N ten minutes to a temperature oi about 950 5 C. and tlien subjecting it to considerable] Witnesses:

pressure. l HENRY .Hnsrnn,

In testimony, that I claim tho 'l'oregoing i WVoumMAnHAUM'. 

